You need to weigh up the risks against the effort: what info is on the disk and how likely is it the new owner of the disk (assuming you wipe it before flogging it off) is going to try to retrieve any residual info.

If you want it done properly, format the drive for a different filesystem (XFS, ext4, JFS, NTFS, ZFS, (V)FAT) then copy data to it from /dev/null and /dev/random (minimum 5x each), then reformat in a totally different FS and start the copy process again. Use all above file systems in that order. No "quick format", the full conversion!

which offers several options which do multiple overwrites to prevent recovery of any data. Read their documentation first if you want an explanation of why single overwrites may not deter a determined cracker.

There is a lot of apocryphal information that suggests that data can be retrieved from disks that have been overwritten several times, even after using such utilities as DBAN.

Having searched a few months ago, just out of interest, not because I had anything to wipe, it became quickly obvious that the cost of retrieval of anything from a disk that has been overwritten even once with zeros, but better with random data, was exorbitant, and only in the case of high forensic need would it ever be contemplated, and even then would probably fail.

The link you provided says;
"Summary:
ATA-SE methodology is superior to Block Erase methodology due to ATA-SE’s ability to overwrite bad blocks, due to it’s reduced time demand and due to it’s improved completion feedback."

I have not found a reliable method to overwrite bad blocks.

Using dd interestingly results in the exact amount of wipe time as a secure ATA command.

By the way, if any of you are interested in using the ATA secure erase, the 'Parted Magic' live cd is great... use the "Disk Eraser".
I understand it to wipe all protected areas and reserved bad block areas by using the secure ATA commands, from a nice little GUI.
You can also use hdparm, but the GUI is pretty stress free.

You may want to see how long it will take for a secure erase, remain seated for a 3TB drive (ouch)....
$ hdparm -I /dev/sda | grep -i "enhanced security"
Results for 1TB;
$ 174min for SECURITY ERASE UNIT. 174min for ENHANCED SECURITY ERASE UNIT.

Thanks all... I'll continue research on my own. Some food for thought eh? It would be nice to know eventually if a simple dd will wipe all reserved/hidden areas of a hard drive.